Input/output mechanism for keyboard printer unit

ABSTRACT

The present invention is intended for use in keyboard printers or typewriters wherein operation of the character type levers is translated by selection control linkage including different combinations of a limited number of latches through a displacement mechanism to select the character on a print head to be printed. The characters selected for printing can be converted simultaneously into coded electrical signals for transmission to a remote station, and the latches also can be electromagnetically actuated in response to receiving coded electrical signals from a remote station. Rocker-type activators are associated with the selection control linkage to selectively open or close electrical switching members in different combinations to generate coded electrical signals representing each character being printed. Further, when coded electrical signals are transmitted back for automatic operation of the typewriter, the electromagnetic actuating means will operate directly on the selector latches through the displacement mechanism over a limited part of each print cycle independently of the rest of the selection control linkage.

United States Patent 1191 Becker 1451 Apr. 9, 1974 INPUT/OUTPUTMECHANISM FOR KEYBOARD PRINTER UNIT [52] U.S. Cl. 197/19 [51] Int. ClB41j 5/30 '[58] Field of Search 197/17, 18, 19,20

[5 6] References Cited UNITED STATES PATENTS 3,413,624 l1/1963 Murdochet al. 197/19 X 3,647,042 3/1972 Smith .z. l97/l9 3,596,745 8/1971Waldenburger.... 197/18 x 3,452,851 7/1969 Holmes 197/19 3,082,8543/1963 Becker et 61.... 197/19 ,233,715 2/1966 Flieg 197/19 3,453,3797/1969 Holmes 178/4.l 3,197,618 7/1965 Stanley et al. 197/20 x 3,391,7747/1968 Greer 197/19 3,294,117 12/1966 Eichemeyer et al. l97/19 X2,735,532 2/1956 Meyer 197/19 1,067,566 7/1913 Wikander.... 197/193,337,019 8/1967 Sasaki 197/l8 y I04 I02 Primary Examiner--Robert E.Pulfrey Assistant ExaminerR. T. Rader [5 7 ABSTRACT The presentinvention is intended for use in keyboard printers or typewriterswherein operation of the character type levers is translated byselection control linkage including different combinations of a limitednumber of latches through a displacement mechanism to v select thecharacter on a print head to be printed. The

characters selected for printing can be converted simultaneously intocoded electrical signals for transmission to'a remote station, and thelatches also can be electromagnetically actuated in response toreceiving coded-electrical signals from a remote station. Rocker-typeactivators are associated'with the selection control linkage toselectively open or close electrical switching members in differentcombinations to generate coded electrical signals representing eachcharacter being printed. Further, when coded electrical signals aretransmitted back for automatic operation of the typewriter, theelectromagnetic actuating means will operate directly on the selectorlatchesthrough the displacement mechanism over a limited part of eachprint cycle independently of the rest of the selection control linkage.

6 Claims, 9 Drawing Figures mam-mm 1914 t 3.8021545 sum 2 of 3 I WM a?I?! 50 V INVENTOR HARO D 0. BECKER ATTORNEYS This invention relates tonovel and improved keyboard printer units, and more particularly relatesto noveland improved means in an input/output typewriter for translatingcharacters into coded electrical signalsas well as for translating thecoded signals back into characters in the automatic operation of thetypewriter.

In the operation of input/output typewriters, as the characters aremanually typed on the typewriter they are simultaneously converted intocoded electrical signals that are recorded or stored at a remotestation. In addition, the same or other signals may be transmitted backto the typewriter and through mechanism responsive to the signals causeautomatic operation of the typewriter to print each characterrepresented by a signal. Typical input/output typewriters of the typedescribed are those set forth and described in United States LettersPat. No. 2,919,002 to L. E. Palmer or No. 3,260,340 to H. C. Locklar etal. wherein a spherical print head bearing columns and rows ofcharacters is selectively rotated and tilted by a displacement mechanismto present the desired character for printing. The displacementmechanism is responsive to actuation of selector latches or couplingelements, limited in number with respect to the number of characters onthe keyboard, which are actuated in different combinations throughselection control linkage set in motion by depression of each key leverin the printing of each character. The linkage will determine in eachcase those latches to remain in the path of an actuating bail which isadvanced in each printing cycle to establish the degree of rotation andtilt of the print head and the character on the print head to be typed.

In positioning the selector latches, the selection control linkagesimultaneously may control opening and closing of electrical switchesfor the conversion of each character into a codedelectrical signal. Inthis connection it is advantageous to provide the most compact assemblyand arrangement which will afford quick, accurate response to limitedmovement of the linkage within each printing cycle with a minimum ofadjustment or maintenance required under repeated, highspeed operations.Additionally, coded electrical signals may be transmitted back to thetypewriter to electromagnetically actuate the same latches whereby tocontrol the degree of rotation and tilt of the print head in selectingeach character for printing in an automaticprinting cycle. Mostdesirably, the electromagnetic means are associated directly with theselector latches of the displacement mechanism in order to position thelatches without the aid of the selection control linkage employed in themanual typing operation and over a very limited part of each printcycle.

It is therefore an object of the present invention to provide for anovel and improved means for translating characters being printed in atypewriter into coded electrical signals in a rapid dependable mannerfor transmission to another location.

It is another object of the present invention to provide means forconverting manual operations performed on a typewriter, keyboard printerand the like into coded electrical signals which is compact and requiresa minimum number of parts and elements in mounting and disposition indirect association with the control linkage and circuitry ofthe'typewriter.

It is a further object of the present invention to provide rocker-typeactivator elements releasably attachable in the path of movement of thecontrol linkage employed for the selection of each character forprinting whereby the activators are quickly andaccurately responsive tomovement of the linkage to control opening andclosing of electricalswitches for coding the information printed, the activator and switchassembly being conformable for use with different types of typewriter orkeyboard printer units, and easily adjustable and servicable once inplace.

It is an additional object of the present invention to provide novel andimproved means for automatically actuating the displacement mechanism ofa typewriter and the like in response to receiving coded electricalsignals which is characterized by its ability to accelerate the speed ofselection of printing each character automatically in response tosignals received from a remote location. 1

It is a still further object of the present invention to provide compactelectromagnetic character selection means directly attachable to atypewriter and energizable in response to receiving remotely appliedcoded electrical signals to activate the displacement mechanism of thetypewriter for printing each character represented by a signal, saidmeans being so disposed and arranged as to operate directly on thedisplacement mechanism and avoid activation through the manual controllinkage of the typewriter thereby greatly accelerating response time andrequiring operation over a limited part of the printing cycle.

It is an additional object of the present invention to provide for anovel and improved means for converting characters printed on atypewriter into coded electrical signals and for activating thetypewriter in response to receipt of coded electrical signals withswitching means to closely time and regulate the time duration withineach printing cycle for coding the characters as they are printed andfor energizing the electromagnetic actuating means in printing eachcharacter. 7

In accordance with the presentinvention, the preferred form is adaptablefor use in a typewriter of the type wherein depression of each key leveris translated through'activation of a selected combination ofinterposers in a selection control linkage to determine the character tobe printed; The number of interposers is limited with respect to thenumber of characters since the interposers canbe actuated in differentselected combinations to represent all of the characters on thetypewriter. In accordance with the present invention, rocker-typeactivators are aligned-in the path of each of the interposers to bemovable in response to advancement of the interposers to control theopening or closing of a corresponding number of switching elementswherein the switch elements are provided with contact arms engageable bythe activators. As a result, a combination of switches may be opened orclosed corresponding to the combination of interposers advanced upondepression of each key lever whereby to generate the same combination ofelectrical signals for transmission to a remote location-In a similarmanner, electromagnetic actuating means is mounted in direct associationwith each of the selector latches to effect displacement of the latchesin response to receipt of coded electrical signals when transmitted backfrom a remote location to operate the displacement mechanism in the samemanner as the character interposers. The electromagnetic actuating meansis so arranged with respect to selector latches associated with theinterposers as to require energization over a minimal time period ineach printing cycle so that the latches can be restored to theiroriginal disposition in ample time for each next cycle in successionwithout use of other restoring means. Hall-effect switches arepreferably employed as the switching elements for coding each characterinto an electrical signal as well as for the timing switch which closelyregulates the timing of the signals for transmission to the remotelocation and energization of the electromagnetic actuating means in eachcycle, the switches being characterized by their rapid response time andlack of bounce or vibration.

The above and other objects, advantages and features of the presentinvention will become more readily understood and appreciated from thefollowing description of a preferred form when taken together with theaccompanying drawings, in which:

FIG. 1 is a top, fragmentary perspective view parts of a conventionalinput/output typewriter utilized in manual keyboard operations.

FIG. 2 is a bottom, fragmentary perspective view illustrating from theunderside of the typewriter unit the selection control linkage forprinting characters on the typewriter together with means for codingeach character into electrical signals and for automatically printingcharacters in response to coded electrical signals.

FIG. 3 is an elevational view of a preferred form of switchassemblyutilized in the formation of coded electrical signals, in accordancewith the present invention.

FIG. 4 is.a plan view of the switch assembly shown in FIG. 3.

FIG. 5 is a side view of the switch assembly shown in FIGS. 3 and 4.

FIG. 6 is a side view in detail of a filter or timing switch assembly.

FIG. 7 is a plan view of electromagnetic actuating means used inautomatic printing operations.

FIG. 8 is a front view in elevation of the electromagnetic actuatingmeans; and

FIG. 9 is a side view of the electromagnetic actuating means.

Referring in detail to the drawings, there is represented for thepurpose of illustration in FIG. 1 a conventional printer unit in which aspherical print head 10 is provided with rows and columns of characters,not shown. The pivot head 10 is selectively advanced into position forprinting by a displacement mechanism which is actuated in response todepression of one of a plurality of key levers, onesuch key lever beingdesignated at 12 which is pivotal about a shaft 13. Whenever a key lever12 is pivoted by its key button 15, a pawl 16 on key lever 12 advances acharacter interposer 17 into alignment with a plurality of selectorbails 20, the latter being disposed for engagement by lugs 21 on thecharacter interposer. Each character interposer has a different lugspacing so that different combinations of selector bails are alignedwith a character interposer 17 in response to depression of each keylever; and each combination of any one or more of the selector bailsaligned with an interposer 17 is representative of the characterdisplayed on the related key button. Each of the selector bails willcontrol movement of an associated latch interposer 24, and of the latchinterposers shown in FIGS. 1 and 2 it will be noted that each has apivotal rod 25 to control movement of a selector or check latch,designated L, out of the path of a common actuating latch bail 26. Eachlatch interposer is normally urged in a rearward direction by a spring25 and each selector latch is biased rearwardly into the path of thebail 26 by a spring 27. The latch bail 26 is caused to be moveddownwardly against those latches L not removed from'its path by thelatch interposers 24, and those latches engaged will operate through thedisplacement mechanism, not shown, to advance the desired character,corresponding to the key lever depressed, into position for printing.

In order to correlate advancement of the actuating bail 26 with movementof the latches L, each character interposer 17 has a special lug 28which when depressed will strike a cycle bail 29 forcing the bail 29 tomove downwardly and, through suitable control linkage represented at 30,actuate a clutch member 32 for rotation of a cycle shaft 34 by a motordrive 35. In each print cycle, the cycle shaft 34 will rotate andthrough intermeshing gears 36, 37 and 38 is operative to rotate a filtershaft 40 through 180. The filter shaft 40 has diametrically opposedblades 41 positioned beneath the character interpose 17 so that in each180 print cycle a blade 41 is engageable with the shoulder 42 on thecharacter interposer 17 to slidably advance and drive the lugs 21 andthe aligned selector bails 20 with the bails engaging lugs 24 to advancetheir respective interposers 24 in a direction lifting their associatedlatches L out of the path of the bail 26.

In FIG. 2 the underside of the typewriter is viewed standing-on end withthe latches L at the bottom and the latch bail 26 is represented indotted form. In a conventional manner, not shown, when the cycle shaft34 is rotated through each print cycle cams on the shaft will engagerollers on a pivotal frame for the bail 26 to force the bail 26 to pivotdownwardly, or to the right in the relation viewed in FIG. 2,causing'displacement of those latches L not moved out of position toactuate the displacement mechanism. Conventionally, in the unit hereindescribed, a limited number of bails 20, character interposers andlatches L are required in relation to the number of characters on thetypewriter unit, that section of the typewriter between the key leversand displacement mechanism herein referred to as the selection controllinkage, and the latches L being the principal selection controlmembers. For the purpose of describing the features of the presentinvention a set of six interposers 24 and associated latches L are givenas an example of the number which may be actuated in different relatedcombination to represent all of the characters on a standard typewriterunit. Of course other parts and elements are associated with the unithereinbefore described to'insure proper correlation between the latchesL, latch bail 26, cycle shaft 34 and filter shaft 40 in the printing ofeach character, it being understood that the foregoing description of atypical typewriter or printer unit is intended as a setting for thefollowing description of a preferred form of the present invention.

It is customary to convert each character typed into coded electricalsignals by positioning a plurality of electrical switches in directassociation with the interposers 24 and to operate the switches inresponse to movement of the interposers. Specifically, movement of aninterposer 24 will operate-an associated switch and through a logiccircuit, signals are transmitted in the same combination as thecombination of interposers 214 that were activated. In accordance withthe present invention and having specific reference to FIGS. 2 and 5 aplurality of switches 50 are attached to a common mounting plate 52which is affixed by spaced brackets 53 behind the typewriter frameportion 54. The switches are mounted in closely spaced, parallelrelation to the direction of travel of the interposers 24, each with aspring-loaded plunger or movable contact member 55 facing in thedirection of travel of an associated' interposer when activated. In thepreferred form,.the switches are solid-state, Hall-effect switches andare normally open so that the depression of the plunger will close theswitches, into a logic circuit on a printed circuit board represented at56, for transmission of an electrical signal to a remote station, suchas, a recording unit. Filter switch 60, to be hereinafter described inmore detail, is operative through a suitable clock circuit tosynchronize transmittal of each combination of signals generated inresponse to activation of the latch interposers 24 in printing acharacter.

In order to transmit movement of the interposers 24 to the switches 50,opposite ends 62 on the plate 52 extend beyond the plungers 55 and areprovided with terminal carrier brackets 63, each bracket having abayonet slot 64 to-receive and support the end of a rocker shaft 65.Rocker-type activators or arms 67 are mounted on the common shaft 65,each activator having a rearwardly extending, flat arm 68 extendingacross the path of movement of the end of an interposer 24 and aforwardly extending, flat contact arm 70 disposed to engage the terminalend of a plunger 55 on each switch 50. The intermediate body portion 72of each activator 67 is provided with a bore for insertion of the shaft65, the activators beingindependently pivotal on the shaft. It will beseen that the interposers 24 have generally C-shaped end portions 73passing through slots in extensions 74 of the frame 54, shown dotted inFIG. 2, and the activators are so aligned that the rocker arms arenormally resting on the end portions 73 inorder to closely followinterposer movement and to impart same in the opposite direction ofmovement against plungers 55. In addition, as noted from FIG. 4, theforward arm portions 70 are formed to compensate for the unequal spacingof the interposers 24 and the equal spacing of the switching whereby toextend over the plunger which is to be responsive to each respectivelatch interposer 24'.

In each printing cycle, depression of each key lever is transmittedthrough the selection control linkage, including selected latchinterposers 24, and in turn movement of the latch interposers will causethe associated activators 67 to be pivoted about the shaft to depressthe plungers of the aligned switches. At the end of each printing cycle,the interposers are restored to their original disposition by the returnsprings 25 shown in FIG. 1, and the outwardly biased, spring-loadedplungers 55 on the switches 50 will cause the activators to return totheir original positions in preparation for the next printing cycle.From the foregoing, the switch and activator assembly is characterizedby its compact mounting and ease of installation so as to be closelysensitive to movement of the latch interposers 24 without directattachment or connection thereto; and any necessary adjust-' ment can bemade through the mounting brackets 53.

operations are carried out without manipulating the se-- lection controllinkage, except for the latches L which are lifted or displacedindependently of the interposer rods 25. Here, it will be noted thateach latch L which has a body L, with a catch or lip L, at one endthereof is slidably supported on a stop member 78 at the lower extremityon each interposer rod 25 and each latch includes a downwardly andforwardly divergent extension plate 80 spaced from the body L, andbeneath the end of the rod 25 so as to define a passage between the bodyL and the extension plate in which a bail 26 is free to move against thecatch L A spring return ele-- ment 82 normally holds the latchdownwardly against the stop 78.

It will be evident that the print head can be advanced to print selectedcharacters under the control of the displacement mechanism by thetransmission of electrical pulses to electromagnetic actuating meansgenerally designated at 84 which is operative to displace a combinationof latches L according to-the coding of electrical signals'applied tothe means 84. Specifically,

.in the form shown in FIGS. 2, 7 and 8, and as viewed juxtaposedrelation to one another within a common,

generally U-shaped frame 86 in substantial alignment with the latches L.The U-shaped mounting frame is attached by mounting brackets 88 to thetypewriter frame 54 with spaced extension plates 89 and 90 projectingupwardly from opposite sides of the frame. The extension plates areprovided with a plurality of slots 92 and 93, a pair of slots beingaligned at opposite sides of each solenoid to receive the forward endportion 94 of an elongated armature plate 95. It will be seen thattheend portion 94 extends across the exposed end'or pole piece 85' of asolenoid 85', and the inner end portion .96 of each plate 95 is situatedbehind a latch extension 80 on each of the latches L. The slots 92 and93 are generally rectangular in configuration and slightlyoverlap theside edges of the frame 86,.the slots being slightly enlarged withrespect to the cross-sectional size of the armature plates 95 wherebyeach plate 95 is free to move a limited distance within its respectivepair of slots toward and away from its solenoid. Thus, each plate 95 isfree to undergo movement in its slots from a, normal position at restaway from its associated sole-,

noid to an inward position, when the solenoid is energized, against theside edges of the frame. When each plate 95 is drawn toward itssolenoid, it willr'ock about the inner side edge of the frame by theslot 92 under sufficient force to overcome the urging of the returnspring 82 and to displace the latch extension 80 and latch L asufficient distance along the interposer rod to withdraw it from thepath of the actuating bail 26. When the solenoid is deenergized, thereturn spring 82 will exert sufficient force on the latch'extension 80to return the latch L to its original position against the end of theinterposer rod 25 and to rock the armature plate 95 in an oppositedirection about the inner side. edge of the frame and away from thesolenoid. The guide slots 92 and 93 in cooperation with the side edgesof the frame will limit movement of the armature plates 95 within veryclose tolerances but will permit sufficient movement of the plate 95 toeffect the necessary displacement of a latch L into and out of the pathof the actuating bail. The armature plates 95 are readily adjustable bybending or shaping the inner end portions 96 in order to align thearmature plate properly between the solenoid frame and latch.

The solenoids 85 are selectively energized through magnet drivers, notshown, and which may be conveniently mounted beneath the solenoidassembly with electrical leads 100 extending through the solenoid frame86 for connection-into each of the solenoids. Generally, the magnetdrivers may tie in with suitable logic circuitry on a printed circuitboard, not shown, which contains the necessary controls to interface theoperational and character elements on the typewriter. Most desirably,while forming no part of the present invention, the logic controlcircuitry will provide the necessary switch-whetting and low impedanceties to a specified logic voltage as well as to provide the necessaryamplification and suppression to operate the solenoids under logiccontrol. Thus, a magnet driver is provided for each solenoid to applythe necessary voltage in operating each solenoid in response to anapplied pulse to the driver from a remote point, such as, from arecording unit; and of course the pulses or signals applied may be thesame as those transmitted through the switch assembly 50 hereinbeforedescribed.

As represented in FIGS. 7 to 9 the solenoid assembly comprises acombination of six solenoids 85 operative to control actuation of sixlatches L, and the spacing between solenoids as well as armatures isregulated to correspond with the spacing between. the selector latches.lnaddition, it will be noted that one of the latches L is offset andaccordingly, one of the armature plates 95 is provided with an offset 95to engage the offset latch portion so as to effect proper movement ofthe latch ,L without interfering with movement of the other latches.Although not shown, an additional solenoid may be provided to controlmovement of a seventh latch which activates a conventional cycle bailand cycle clutch, not shown, for rotation of the cycle shaft 34through'each print cycle.

In each printing cycle, the solenoids are energized upon receiving acoded electrical signal over a time duration controlled by the filter ortimer switch 60. As best seen from FIGS. 2 and 6, the filter switchassembly 60 comprises a pair of switches 102 and 103 mounted on anextension 108 of the frame 54 where the opening and closing of eachswitch is controlled by separate cam elements 104 and 105, respectively.The cam elements 104 and 105 are mounted for rotation on the filtershaft 40 and are rotationally offset from one another, as illustrated, apredetermined number of degrees to control the period of energization ofthe solenoids within each 180 print cycle. Thus for example the cam 104may be set to close its switch 102 by depression of plunger 102 at somepoint approximating 30 into each printing cycle to energize thesolenoids, and the cam 105 may be set to deenergize the solenoids within10 to 30 later by depressing the plunger 103' on switch 103 to close theswitch and deenergize the solenoids well in advance of the next printingcycle. Thus the solenoids can be accurately picked or energized over buta limited portion of the cycle to remove a selected combination oflatches L from the path of the bail 26, and thereafter may bedeenergized to remove any residual magnetism and restore the latches Lin advance of each next cycle in succession. This achieves closeaccurate control over the movement of the latches while permittinghigh-speed printing in a reliable efficient manner. In order to furtherminimize residual magnetism, preferably the pole pieces are covered witha Mylar tape and the duty cycle within each print cycle may be closelyset to energize or deenergize the solenoids over 10 to 30 of the printcycle, since the armature plates will operate directly on the selectorlatches and not through the interposer rods 25.

In a typical printing operation, each character to be printed is codedthrough the switch assembly 50 as hereinbefore described. When thetypewriter is set for automatic operation, the automatic printing of thecharacters progresses by application of the coded signals which may beapplied serially in the form of bits into a shift register. After thelast bit representing a character is clocked into the shift register,the bits may be loaded in parallel into a storage register and a clockcircuit simultaneously activated to set or reset a bistable devicecontrolling a second clock circuit, such as, a one-shot delay. If theprinter mechanism is in condition to receive, as controlled by aninterlock switch on the printer, the one-shot delay is activated in thesolenoid for the cycle shaft where the cycle shaft is energized toinitiatethe print cycle by releasing the cycle shaft for rotation of thefilter shaft 40 and associated blades. The terminal leads, not shown, onthe switches 102 and 103 are connected into the second clock circuit toregulate the period of energization of the solenoids in each cycle.Thus, when the one-shot delay is activated in the second clock circuit,energizing pulses are not gated to energize the magnet drivers until thefilter switch is permitted to close at the desired point into the cycle;and further, the magnet drives are not deenergized until the switch isopened at the selected point later in the cycle as regulated by thesecond filter switch 103. If for any reason the filter switch 103 shouldfail to function properly in each cycle, the second clock circuit ordelay may time out at the end of the cycle to deenergize the solenoids.The energizing pulses are applied only to selected magnet drivers 100corresponding to the combination of pulses in the storage register foreach print cycle and will activate only those latches corresponding tothe combination of pulses applied to displace the latches out of thepath of the actuating bail. The actuating bail 26 will engage thoselatches remaining in its path to effect selective rotation and tilt ofthe print head through a conventional displacement mechanism, not shown,to print the desired character.

Thus there has been provided in accordance with the present invention anovel and improved electromagnetic input mechanism for controlling asingle element print head to advance different characters into printingposition by selective actuation of different combinations of a limitednumber of latches associated with the selection control linkage. Thesolenoids in cooperation with the armature plates are able to actuatethe latches over a limited time interval within each print cycle underthe control of the filter switch which is controlled in opening andclosing through the cycle shaft. The electromagnetic input mechanismwill operate directly on the selector latches L without disturbing therest of the selection control linkage; and conversely the selectioncontrol linkage may operate in the same manner upon the selector latchesL for selection of each character through the same displacementmechanism without disturbing the electromagnetic input mechanism and theactivators and switch assembly will respond to movement'of the selectioncontrol linkage in response to manual depression of the key leverindependently of the operation of the electromagnetic input mechanism.However, the selection control linkage and electromagnetic inputmechanism will operate through the same displacement mechanism tocontrol printing of each character.

It is to be understood from the foregoing that various modifications andchanges may be made in the construction and arrangement of elementscomprising the preferred form of the present invention, such as, for usein other forms of printer apparatus than that described, withoutdeparting from the spirit and scope of the present invention.

What is claimed is:

1. In an input/output typewriter having a plurality of interposersarranged in side-by-side relation to one another for independentmovement of selected ones of said interposers by advancement means atone end of the interposers in response to depression of a key leverbetween an inactive position and an active position in advancingdifferent selected characters on a print head into printing positionthrough a corresponding number of selector latches, each latch having abody with a catch for selective engagement by a latch bail in thetypewriter and disposed on an interposer to follow movement of eachrespective interposer, and each of the latches being slidable in onedirection independently of said interposers and operative in combinationto advance different selected characters ofthe print head into printingposition, the combination therewith comprising:

electromagnetic actuating means for each of said selector latches,

a frame assembly mounting said electromagnetic actuating means inadjacent spaced relation to said selector latches, each selector latchincluding an extension portion extending awayfrom the body thereof inspaced relation to the catch and to the interposer associated with thelatch and defining a passage between the body and the extension portionin which the latch bail is free to move against the catch,

an armature plate associated with each of said electromagnetic actuatingmeans and movable in response to energization of its electromagneticactuating means into engagement with said extension portion on therespective selector latch to slidably displace said selector latchindependently of its respective interposer, and

spring return means to restore each latch to its original position upondeenergization of each respective electromagnetic actuating means.

2. In an input/output typewriter according to claim 1, said frameassembly being of generally U-shaped c.on-' figuration for mounting ofsaid actuating means in spaced parallel relation to said interposers,said frame assembly having opposite side portions extending beyond saidactuating means with aligned slots in the sides of said frame assemblyfor insertion of said armature plates, said plates being movable withinthe slots in response to energization of the actuating means toselectively displace an aligned selector latch.

3. In an input/output typewriter according to claim 2, each of saidactuating means being defined by a solenoid responsive to an appliedelectrical signal to be energized for displacing an associated latch,and a timer switch common to said solenoids to selectively control theperiod of energization of said solenoids in each printing cycle.

4. In an input/output typewriter according to claim 1, wherein the endof said interposersopposite to said one end extends through anassociated latch, and wherein said extension portion of each latch isdisposed on the opposite side of the body of the latch from the said oneend of said interposers.

5. In an input/output typewriter according to claim 13, said extensionportion of each latch being connected to the body of the latch at oneend and inclining away therefrom whereby the opposite end of theextension portion is spaced from the body of the latch and said oppositeend of the interposer and disposed for engagement by an armature plate,and furtherincluding stop means on said opposite end of the interposerfor engaging the body of the latch when said interposer is moved by theadvancement means to prevent said latch bail from engaging the catch onthe latch.

6. In an input/output typewriter wherein selection control linkage isprovided with a plurality of interposers disposed in side-by-siderelation to one another, selected interposers being independentlymovable in response to depression of a key lever, a corresponding numberof selector latches, each latch disposed at the end of an interposer tofollow movement of its respective interposer and being slidable in onedirection independently of its interposer, said latches being operativein combination to advance different selected characters of the printhead into printing position, the improvement comprising:

signal generating means for generating electrical signals representativeof each character selected in response to movement of selectedinterposers, said generating means including an electrical switch memberaligned in closelyspaced relation to one end of a respective interposeropposite to the end adjacent to said latch, each switch member having amovable plunger operative to open and close each switch member.

activator means comprised of a unitary plate-like structure havingopposite substantially flat faced arm portions extending between the oneend of the interposer and movable plunger of each switch member, anenlarged intermediate body portion between the flat faced arm portions,a shaft passing through the intermediate body portion about which theactivator means can pivot, said activator means being responsive tomovement of each interposer against a flat face of an arm portion of theactivator means to cause said activator means to pivot about the shaftand engage its respective plunger to effect closing of its respectiveswitch member for generation of an electrical signal; electromagneticactuating means associated with each of said selector latches includinga control arm associated with each of said actuating means and movablein response to energization of said actuating means to displace analigned selector latch independently of its respective interposer, and

spring return means to restore each latch to its original positionagainst the end of its interposer upon deenergization of each respectiveactuating means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,802,545 D t d 9 April 1974 Inventor(s) Harold D. Becker It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown'below:

In the Specification:

Column 4, line 26, cancel "interpose" and substitute --interposer-- Inthe Claims:

Column l0 line l5, cancel "13 and substitute "4-- Signed and sealed this30th day of July 197A.

(SEAL) Attest:

MCCOY M. GIBSON, JR. 0. MARSHALL DANN Attesting Officer Commissioner ofPatents

1. In an input/output typewriter having a plurality of interposersarranged in side-by-side relation to one another for independentmovement of selected ones of said interposers by advancement means atone end of the interposers in response to depression of a key leverbetween an inactive position and an active position in advancingdifferent selected characters on a print head into printing positionthrough a corresponding number of selector latches, each latch having abody with a catch for selective engagement by a latch bail in thetypewriter and disposed on an interposer to follow movement of eachrespective interposer, and each of the latches being slidable in onedirection independently of said interposers and operative in combinationto advance different selected characters of the print head into printingposition, the combination therewith comprising: electromagneticactuating means for eAch of said selector latches, a frame assemblymounting said electromagnetic actuating means in adjacent spacedrelation to said selector latches, each selector latch including anextension portion extending away from the body thereof in spacedrelation to the catch and to the interposer associated with the latchand defining a passage between the body and the extension portion inwhich the latch bail is free to move against the catch, an armatureplate associated with each of said electromagnetic actuating means andmovable in response to energization of its electromagnetic actuatingmeans into engagement with said extension portion on the respectiveselector latch to slidably displace said selector latch independently ofits respective interposer, and spring return means to restore each latchto its original position upon deenergization of each respectiveelectromagnetic actuating means.
 2. In an input/output typewriteraccording to claim 1, said frame assembly being of generally U-shapedconfiguration for mounting of said actuating means in spaced parallelrelation to said interposers, said frame assembly having opposite sideportions extending beyond said actuating means with aligned slots in thesides of said frame assembly for insertion of said armature plates, saidplates being movable within the slots in response to energization of theactuating means to selectively displace an aligned selector latch.
 3. Inan input/output typewriter according to claim 2, each of said actuatingmeans being defined by a solenoid responsive to an applied electricalsignal to be energized for displacing an associated latch, and a timerswitch common to said solenoids to selectively control the period ofenergization of said solenoids in each printing cycle.
 4. In aninput/output typewriter according to claim 1, wherein the end of saidinterposers opposite to said one end extends through an associatedlatch, and wherein said extension portion of each latch is disposed onthe opposite side of the body of the latch from the said one end of saidinterposers.
 5. In an input/output typewriter according to claim 13,said extension portion of each latch being connected to the body of thelatch at one end and inclining away therefrom whereby the opposite endof the extension portion is spaced from the body of the latch and saidopposite end of the interposer and disposed for engagement by anarmature plate, and further including stop means on said opposite end ofthe interposer for engaging the body of the latch when said interposeris moved by the advancement means to prevent said latch bail fromengaging the catch on the latch.
 6. In an input/output typewriterwherein selection control linkage is provided with a plurality ofinterposers disposed in side-by-side relation to one another, selectedinterposers being independently movable in response to depression of akey lever, a corresponding number of selector latches, each latchdisposed at the end of an interposer to follow movement of itsrespective interposer and being slidable in one direction independentlyof its interposer, said latches being operative in combination toadvance different selected characters of the print head into printingposition, the improvement comprising: signal generating means forgenerating electrical signals representative of each character selectedin response to movement of selected interposers, said generating meansincluding an electrical switch member aligned in closely-spaced relationto one end of a respective interposer opposite to the end adjacent tosaid latch, each switch member having a movable plunger operative toopen and close each switch member, activator means comprised of aunitary plate-like structure having opposite substantially flat facedarm portions extending between the one end of the interposer and movableplunger of each switch member, an enlarged intermediate body portionbetween the flat faced arm portions, a shaft passing through theintermediaTe body portion about which the activator means can pivot,said activator means being responsive to movement of each interposeragainst a flat face of an arm portion of the activator means to causesaid activator means to pivot about the shaft and engage its respectiveplunger to effect closing of its respective switch member for generationof an electrical signal; electromagnetic actuating means associated witheach of said selector latches including a control arm associated witheach of said actuating means and movable in response to energization ofsaid actuating means to displace an aligned selector latch independentlyof its respective interposer, and spring return means to restore eachlatch to its original position against the end of its interposer upondeenergization of each respective actuating means.